#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int Fact(int i)
{
	int fact = 1;
	for (int c = i; c; c--)
	{
		fact =fact*c;
	}
	return fact;
}

int main()
{
	int i;
	scanf("%d", &i);
	printf("%d", Fact(i));
	return 0;
}